<template>
  <div>
    <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
       <div class="iconfont back-icon-back">&#xe624;</div>
    </router-link>
    <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
     <router-link to="/">
       <div class="iconfont header-fixed-back">&#xe624;</div>
     </router-link>
     景点详情
    </div>
  </div>
</template>

<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      // console.log(document.documentElement.scrollTop)// 获取页面滚动的top值
      const top = document.documentElement.scrollTop
      if (top > 60) { // 页面滚动到60时。显示隐藏标题
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = opacity
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
@import '~styles/varibles.styl'
  .header-abs
    position: absolute
    margin-left: .2rem
    top: .2rem
    text-align: center
    width: .6rem
    height: .6rem
    line-height: 0.6rem
    border-radius: .3rem
    background: rgba(0, 0, 0, .8)
    .back-icon-back
      color: #fff
      font-size: .3rem
      margin-left: -0.06rem
  .header-fixed
    z-index: 2
    position: fixed
    top: 0
    width: 100%
    max-width: 13rem
    overflow: hidden
    height: $headerHeight
    line-height: $headerHeight
    background: $bgColor
    text-align: center
    color: #fff
    font-size: .4rem
    .header-fixed-back
      position: absolute
      top: 0
      left: .0.5rem
      width: .64rem
      text-align: center
      font-size: .4rem
      color: #fff
</style>
